In the railroad industry it is well known, prior to the present invention, to use standard railcar couplers. These couplers are used to connect adjacent ends of a pair of railway cars together to form a train consist. It is also known that these couplers have been approved for service in interchange by the Association of American Railroads (AAR). In this application, for example, these standard couplers were generally designed in a manner such that both the connecting together and disconnecting of individual railway cars could be readily accomplished. In addition, these standard couplers enable the train consist to be made in an expeditious manner. Further, such standard couplers enable individual railcars to be easily separated to facilitate their loading and unloading as necessary during service.
However, in more recent times, it has been discovered by the railroad industry that the interconnecting together of a number of railway cars to form a generally semi-permanent unit will achieve a number of distinct advantages. When, for example, such railroad cars are particularly adapted for use in what is known in the industry as "piggyback" service and have been joined together in this manner, such advantages are readily achieved. Such railroad cars which have been joined in this generally semi-permanent fashion are commonly referred to in the railroad industry as a "10-pack." As is well known, these 10-pack units do not require the use of such standard railway couplers discussed above except between units. In other words, on each end of such 10-pack units. Because such 10-pack units are normally only broken on a periodic basis, is the primary reason why the use of these standard railway couplers is not required. In practice, these 10-pack units will only be broken when either maintenance or replacement of either an individual coupling component or some other car component must be carried out. It is, therefore, obvious that by this arrangement considerable cost-savings can be achieved by the railroad industry. These cost-savings, for example, are primarily derived from lower weight which will improve fuel efficiency, fewer railway trucks, reduced maintenance, and lower equipment cost. Such lower weight and reduced equipment cost being derived, in part, by substantially reducing the need for draft gears and the number of railway car trucks required in such 10-pack units.
With the ever increasing use of these normally semi-permanent coupling arrangements and with the need for heavier loads to be carried by modern railway service, it has been recognized that it is of the utmost importance for a close-buttoned relationship to be maintained between the coupler draft components during service on the track structure. Such close-buttoned relationship is required in order to achieve a reduction in the effects of the impact forces which are normally encountered under buff conditions of train operations.
In U.S. Pat. No. 4,258,628 one of the prior art type articulated coupling arrangements is taught. This articulated coupling arrangement is used to interconnect adjacent ends of a pair of railway cars together in a semi-permanent manner to form a 10-pack. This particular articulated coupling device includes a male connection member which is secured to a first end of a first railway car body member and a female connection member which is secured to an adjacent end of a second railway car body member. The female connection member, in this coupling arrangement, is rotatably engaged in a center plate bowl portion of a bolster member of a railroad car truck. This rotatable engagement is carried out in a manner that is well known in the railway art. The outer end of the male connection member is positioned for relative movement in a cavity that is formed in the outer end of such female connection member. Both the male connection member and the female connection member are joined, in such semi-permanent manner, by a pin member. As taught in this prior art reference, such pin member is positioned in a vertical direction and is disposed in vertically aligned apertures formed in each of such male connection member and such female connection member. The vertically disposed aperture formed in the outer end of the male connection member for receiving such pin member therein must be somewhat larger than the pin member itself in order to allow certain movements such articulated coupling arrangement will be required to make. A rear surface portion of the aperture formed in such male connection member which receives the pin member therein has a concave configuration in a horizontal direction and a convex configuration in a vertical direction. This particular configuration will enable both the male connection member and the female connection member to move in relationship to one another in each of a horizontal direction and a vertical direction. Additionally, this configuration will provide a relatively substantial area of surface contact between the rear surface of the pin aperture and the pin member. Obviously this also provides a relatively substantial surface area which is subjected to frictional wear.
The outer end surface of the outer end portion of such male connection member includes a convex configuration which is positioned to abut against a complimentary concave surface formed on a front face portion of a follower member. In this articulated coupling device, the follower member is carried within the rear portion of the cavity that is formed in the outer end portion of such female connection member. Formed on the rear face portion of such follower member are a pair of vertically disposed slot-like cavities. Each of these vertical slot-like cavities has a resilient element disposed therein. At least a portion of such resilient element protrudes outwardly from such rear face portion of such follower member. The exposed outer surface of each such resilient element is slidably engaged by a vertically disposed wedge-like element. This wedge-like element is provided in this articulated coupling arrangement so that during service such follower member and such male connection member will be urged forward. In this manner, the rear surface portion of the aperture formed in such male connection member will be maintained substantially in intimate contact with the pin member at all times so that minimum slack in such articulated coupling arrangement can be ensured.
Furthermore, such intimate contact has generally been found necessary in these prior art articulated coupling arrangements, because most of the articulated connecting components are cast members. In order to provide any significant reduction in the manufacturing cost of this coupling arrangement, such cast members normally will receive very little, if any, finish type machining to provide either the necessary or the desirable dimensional control. As a result of this lack of finish type machining, it is generally rather difficult to provide an articulated coupling arrangement of this type which will possess the self-adjusting capability required under various wear conditions. Such self-adjusting capability being necessary in order to minimize as much a possible the slack encountered in the various connections during service in a train consist.
Other prior art type articulated coupling arrangements are taught in U.S. Pat. No. 3,716,146 and Canadian Patent number 1,231,078.